Researchers at the Technion Faculty of Physics have successfully demonstrated an innovative way to transfer atoms between locations using quantum tunneling and optical tweezers, an achievement that could significantly advance quantum technology. Led by Professor Yoav Sagi and doctoral student Yanay Florshaim from the Solid State Institute, the research reveals how atoms can be moved from one point to another without physically traveling the distance between them, thanks to a quantum effect known as tunneling. The findings were published in the journal Science Advances.
At the core of this experiment are optical tweezers, a tool that uses laser light to capture and manipulate microscopic particles, including atoms and molecules. Optical tweezers work by focusing a laser beam to a tiny spot, generating an optical potential that can “trap” particles in place or move them as needed. This potential results from the interaction of light with matter, creating a force proportional to the light’s intensity. While too weak to impact macroscopic objects, this force is powerful enough to influence tiny particles, such as atoms, enabling researchers to capture and manipulate them precisely.
Optical tweezers have become essential in fields like physics and biology, and the development of this tool earned physicist Arthur Ashkin the Nobel Prize in Physics in 2018. In their experiment, the Technion team utilized a linear arrangement of three optical tweezers, placed in a row. By adjusting the distances between each pair of adjacent tweezers, they could dynamically control the rate of quantum tunneling between the traps, which ultimately enabled them to transfer atoms between the two outer tweezers.
Quantum tunneling is a unique property of the quantum world, allowing particles to cross barriers that would be insurmountable under classical physics. For instance, imagine a marble sitting in a bowl; it would normally need sufficient energy to roll over the bowl’s edge. In quantum physics, however, particles like atoms can “tunnel” through such barriers without requiring extra energy, effectively appearing on the other side as though they had bypassed the barrier altogether. This remarkable phenomenon underpins the Technion team’s atom-transfer method.
Through careful manipulation of the tunneling rates, the researchers were able to move atoms from one side of the setup to the other smoothly and efficiently. Yet, intriguingly, despite traveling between the two outer tweezers, the atoms almost never appeared in the middle trap. This effect can be explained by quantum interference, a core principle of quantum mechanics. In this experiment, atoms are described by wave packets, meaning they exhibit wavelike properties. The specific setup of the three tweezers causes these waves to interfere destructively in the center trap, effectively canceling out the probability of finding atoms there.
This interference pattern highlights the non-intuitive nature of quantum mechanics, where particles like atoms can exhibit behavior more like waves than solid objects. By exploiting this wave-like nature, the Technion team achieved a controlled transfer of atoms that bypassed the middle region entirely, which is not possible in classical systems.
This transfer scheme represents the first demonstration of moving atoms in this way and holds promise for future applications in quantum technology. Controlled atomic movement is essential for the development of quantum computing platforms and quantum simulation systems, where precise placement and transfer of atoms are crucial for constructing complex quantum states. The Technion researchers believe that this achievement could contribute to new quantum platforms by enabling more efficient and precise atomic manipulations.
The results from this experiment open exciting possibilities for quantum physics and technology. Precise control of atom tunneling between optical traps could lead to new ways of building and operating quantum systems, essential for future quantum computers, sensors, and other advanced technologies.